1. Field of the Invention
The present invention relates to a plasma display device.
2. Description of the Related Art
A plasma display device is a flat panel display capable of displaying color images by generating ultraviolet light through high-voltage gas discharge, and lighting fluorescent agents of various colors painted to each pixel within the panel.
The technology related to plasma display devices has advanced remarkably during the recent years, and the plasma display devices have now reached amass production state. There exists a competition in developing a large-size plasma display device that is bright, has a wide viewing angle, has an even luminance throughout the whole screen, and that is free from distortion, effusion or mismatch of colors.
However, according to the conventional plasma display devices, a beautiful image is provided only when viewed in a dark room. The image provided by the plasma display is not bright enough to be viewed at a bright place, for example, outdoors.
The structure of a plasma display device according to the prior art is explained with reference to FIG. 5.
Electronics 3 are connected to a display module 10 through a flex lead 5. Tempered glass 9 is mounted on the display surface of the display module 10 via space 7.
The display module 10 defines discharge spaces 20 by a back surface glass 11 placed to the side of the electronics 3, separation walls 15, and a front glass 13 placed to the side of the tempered glass 9 and superposed to the back surface glass 11 through the separation walls. Data electrodes 12 are mounted on the back surface glass 11, and scan electrodes 14 are mounted on the front surface glass 13, which are covered with dielectric layers 18 and 19. Fluorescent 17 of three colors (17R, 17G, 17B) are applied on each discharge space corresponding to each pixel.
High voltage is impressed to electrodes 12 and 14 of the plasma display device formed as explained above, and gas discharge is performed within the discharge space 20 filled with neon gas including argon. Ultraviolet light is generated in each discharge space 20, and causes the fluorescent 17 of the corresponding pixel to glow.
One cause of insufficient brightness of the plasma display device is that not all of the visible radiation from the fluorescent caused by the ultraviolet light generated by the gas discharge is radiated toward the display surface or front glass 12. Visible radiation is also radiated toward the back surface glass 11 and the side surfaces (separation walls 15), and perpendicular members (such as glass) absorb the visible radiation.
In order to improve the radiation efficiency toward the display surface, there are attempts to color the dielectric layer 18 mounted to the back surface glass 11 white, so that it may reflect the visible radiation. However, the effect is not satisfying.
Moreover, many electronics 3 are mounted to the back surface of the display module 10. The heat generated form the display module 10 heats the electronics 3, causing problems.
This is because the gas discharge and the fluorescent of the display module 10 generates electromagnetic wave energy having various wavelengths, such as ultraviolet, visible radiation, heat wavelength energy and radio wavelength energy. The white-colored dielectric layer 118 mounted to the back surface of the module improves the luminance of the display by reflecting the visible radiation (electromagnetic wave having a wavelength of 0.38-0.78 micron) generated from the fluorescent. However, the white dielectric layer does not reflect electromagnetic wave energy having a long wavelength (0.78-100 micron) classified as heat wave energy, or radio wave energy (electromagnetic wave energy having a wavelength of 100 micron or greater).
Even further, the electromagnetic wave energy that has not been reflected by the dielectric layer is absorbed by the fluorescent, the white-colored dielectric layer 18 formed on the back surface, and the back surface glass plate 11 of the display module 10, and there, the electromagnetic wave energy is converted into heat energy. The heat energy causes the temperature of the back surface portion of the display module 10 to increase.
From the above reasons, there is a need to forcedly diffuse the heat of the display module, not only to protect the module but also to protect the electronics connected to the module.
The present invention provides a plasma display device having improved luminosity and bright image quality with low power consumption, and with reduced electromagnetic wave energy radiated toward the back surface of the display module equipped with electronics converting into heat energy.
The plasma display device according to the present invention comprises a display module equipped with an array of luminescent pixels, and electronics connected to the back surface of the display module wherein the front surface of the display module is a display surface, and the surface of the luminescent pixels opposite said display surface is a reflection surface.
The display module of the plasma display device according to the present invention comprises a back surface glass plate having discharge electrodes and to which are connected electronics; a front surface glass plate mounted on and opposing to the back surface glass plate via separation walls and having discharge electrodes; and luminescent pixels defined by the back surface glass plate, the separation walls and the front surface glass plate; wherein the luminescent pixels are formed so that at least the surface of the back surface glass plate opposite the display surface is a reflection surface. In another example, the luminescent pixels of the display module are formed so that all surfaces other than the surface of the front surface glass plate are reflection surfaces.
According to another aspect of the invention, the reflection surface is formed by metal plating, or by adhering metal leafs. In another example, the reflection surface opposing the display surface has a concave surface, and the light reflected from the reflection surface is condensed at the display surface.
A method for manufacturing a display module of a plasma display device according to the present invention comprises mounting electrodes covered with dielectric on a back surface glass plate and on a front surface glass plate; mounting separation walls on the back surface glass plate, thereby forming discharge space; forming a reflection surface on walls of each discharge space; and superposing the front surface glass plate functioning as a display surface on the separation walls opposite the back surface glass plate, thereby forming luminescent pixels.
According to the present invention, the shape of the discharge spaces (luminescent pixels) are changed, and reflection surfaces formed by metal plating and the like are provided to the areas that are expected to reflect the electromagnetic wave. Thereby, any electromagnetic wave energy regardless of its wavelength can be reflected toward the front direction of the pixel to improve the brightness of the display, and to minimize the radiation of energy toward the back surface of the, module.